Oscillating steam-engine



m S a m h S 4 M A H A R G A W (No Model.)

OSG ILLATING STEAM ENGINE.

Patented Apr. 21,1891.

(No Model.) 4 Sheets-Sheet. 2. W. A. GRAHAM.

OSGILLATING STEAM ENGINE.

No. 450,934. Patented Apr. 21, 1891.

(No Model.) 4 Sheets-Sheet 3. W. A. GRAHAM. OSGILLATING STEAM ENGINE. No. 450,934. Patented Apr. 21,1891.

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4 Sheets-Sheet 4.

(No Model.)

W. A. GRAHAM. OSCILLATING STEAM ENGINE.

Patented Apr. 21 1891.

llllllllllil gwwmto'c mu m I I IIqIH UNITED STATES PATENT OFFICE.

\VILLIAM A. GRAHAM, OF CARLISLE, PENNSYLVANIA.

OSCILLATING STE AM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 450,934, dated April 21,1891.

Application filed November 15, 1890. Serial No. 371,490. (No model.)

To all whom it may concern.-

Be it known that 1, WILLIAM A. GRAHAM, of Carlisle, in the county of Cumberland and State of Pennsylvania, have invented certain new and useful Improvements in Oscillating Steam-Engines; and I do hereby declare the following to be a full, clear, and exact descrip tion of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an improvement in oscillating steam-engines, the object being to provide means for reversing the engine for graduating the speed and keeping it uniform, and which has heretofore resulted from the dependence of the cylinder for its oscillatory motion upon the connection of its piston-rod with a crankshaft, which resulted in wearing the stuffing-box and piston-rod at opposite points of contact.

ith these objects in view my invention consists in an oscillating cylinder-valve-chest, and valve in combination with a sliding connection between some stationary part of the engine and the valve-axle capable of being moved to one side or the other of the axle, whereby the engine may be run forward or be reversed or be stopped or started at the pleasure of the engineer.

The invention further consists in a guideframe connected with the oscillating cylinder, and within which the piston-rod of the cylinder reciprocates, whereby all strain, friction, and wear on the sides of the piston-rod and in the stuffing-box at the pointof contact are absolutely prevented.

The invention still further consists in certain novel features of construction and combinations of parts, as will be hereinafter described, and pointed out in the claims.

In the accompanying drawings, Figure 1 is a side elevation of my improved engine. Fig. 2 is a view partly in section and partly in elevation. Fig. 3 is a view in end elevation, taken at right angles to the View shown in Fig. 1. Fig. 4 is a plan view, and Figs. 5, O, and 7 are details.

A represents the frame of the engine, preferably made in one casting and comprising two standards a a, connected by a base I) at the bottom, and provided with bearings e (Z at the upper ends, and at or near the center,

respectively, to receive the trunnions of the cylinder and the main shaft, caps e c being securely bolted over these shafts to retain them in their bearings.

13 represents the cylinder, it being constructed with hollow trunnions 1 1, adapted to rock in the bearings c c as the engine operates. Pistou C is fitted to reciprocate in the cylinder, and this piston may have the usual tight fit against the walls of the cylinder.

A cylindrical valve-chest 3 is located at one side of the cylinder, as shown in Fig. 1. This valve-chest has a slightly-tapering valve-seat formed therein, and the valve 4 is of corresponding shape and is neatly fitted to this seat, against which it rocks ,as the cylinder oscillates. The valve consists of a hollow plug made solid through the middle, where it joins the axle 5, and is provided with recessed ends. Two ports 6 6 are formed in the valve extending from the inside to the exterior, and between. these ports an exhaust-port 7 is formed. The usual steam-ducts lead to opposite ends of the cylinder, and each port in the valve is adapted to register alternately with one of the ducts and the exhaust-port. Steam is supplied through one of the trunnions 1 and exhausted through the other.

Thus far the parts are precisely the same as in my former patent, No. 113,506, dated October 22, 1889; but as the remaining portions of my present invention comprise a material departure from the invention covered by said Letters Patent 1 will proceed with a detailed description of the novel features, and, first, the reversing mechanism.

A segment 10, formed as shown in Fig. 5, is preferably bolted to the outer end of one of the bearings c. This segment is provided with a hole 11, through which the live-steam pipe passes. Reversing-lever 12 straddles this segment and ispivoted at one end to the arm 13 of the segment, and this reversing-lever has a spring slide-latch adapted to engage the teeth 14c on the rounded edge of the segment. The teeth on this segment are in three sets. \Vhen the lever is placed in position for the latch to engage the lower set of teeth, the engine is made to run forward, and when the latch engages the upper set the engineis reversed and the speed is decreased as the reversing-lever is moved farther-from the ICO center and its speed is increased as the lever is moved toward the axle of the valve, and when the lever is moved so that its center is opposite the axle of the valve the engine is stopped. This is the position shown in Fig. 1 with the latch in engagement with the tooth or teeth at the center of the segment.

The rocking of the valve is regulated by the following means: The axle of the valveis provided with a guide-bar 15. This bar is composed of two narrow plates with parallel edges secured together at their ends. Thimble 16 has an opening 17 therein a trifle larger than one of these plates and whereby the thimble is loosely mounted on the guide-bar, so as to slide freely back and forth. The other end of the thimble extends loosely through an elongated slot 18, formed in the reversing-lever, in relation with which the thimble slides as thelever is swung back and forth to control the engine. There is also a slot (designated by numeral 10) formed in the segment, through which the thimble also passes. This slot is restricted at each end to about correspond in width with the diameter of the thimble, so that when the lever is thrown to place the thimble in these restricted portions of the slot, the thimble is confined and prevented from lateral play. Necessarily the center of the slot has to be large to permit lateral play as the thimble approaches the axle of the valve, as otherwise parts would have to break. Now by means of the lever audits connection with the thimble the rock'- ing of the valve is regulated, the principle of action being dependent upon the length of the radius from the thimble, which is the fixed point or center from which the valve swings, to the axle of the valve, and this change of radius, or, in other words, the length of swing from the fixed center, is effected. In this manner the valve is made to oscillate in the opposite direction from the motions of the cylinder, and thus the ports and ducts are made to register and close at proper intervals to control the steam and drive the engine.

Reference has been made to a device for relieving lateral pressure, friction, and wear on the stuffing-box of the cylinder. This consists of a guide-frame 45 secured to the end of the cylinder. two plates secured together at their outer ends and arranged to loosely embrace the piston-rod, the piston-rod being connected with a crank on the main shaft, and as it moves with the crank it strikes the guide and carries it with it and thus oscillates the cylinder, so that, instead of moving the cylinder by the lateral movement of the piston-rod.

against it, this strain -is taken by the guideframe.

The strap-head consists of a U-shaped yoke and a plate secured over its opening by screws or other means 46 46. The boxes are placed in the yoke and held there by the plate, and

This preferably comprises they are set up against the crank as it becomes worn by a set-screw 4'? 1n the end provided for the purpose. The screws lb 4.6 operate in a long slot 49 in the guide-frame as 7 the piston-rod reciprocates, and in this manner the operation of the parts is rendered more perfect.

The complete operation is as follows: The steam is admitted through one of the trunnions l and passes directly into the valvechest, where it is directed alternately to the opposite ends of the steam-cylinder. This reciprocates the piston-rod, which in turn drives the shaft. The engine is stopped and started and made to run forward or backward by manipulating the reversing lever, as through it the motion 'of the valve is regulated or its motion prevented.

Changes in the constructive details of the invention may of course be made Without departing from the spirit and scope of my invention, and henceI do not wish to limit myself to the precise construction herein set forth; but,

Having fully described my invention,what I claim as new, and desire to secure by Letters Patent, is-

1. In an engine, the combination, with an oscillating valve-chest and a valve, of a thimble having loose sliding connection with the valve-axle and capable of being set at different positions 011 either side of said axle, substantially as set forth.

2. In an engine, the combination, with a valve-chest and a valve constructed to oscillate therein, of a device arranged to slide back and forth across the end of the valvestem,and a lever operatively connected with 7 this device, whereby the position of the latter relative to the axle of the valve is changed, substantially as set forth.

3. In an engine, the combination, with a valve-chest and a valve fitted to turn therein, of a guide extending transversely across the end of the valve-stem, a thimble having sliding connection with this. guide, and a lever having slots therein adapted to looselyreceive the thimble, whereby the position of the thimble maybe changed by a motion of the lever, substantially as set forth.

4:. In an engine, the combination, with a valve-chest and a valve fitted and adapted to rock therein, of a movable center extending at right angles to the axle of the valve,

into the restricted ends of the slot in the segment to keep the engine in motion, substantially as set forth. i

6. In an engine, the combination, with a frame, an oscillating cylinder, a valve-chest thereon, and a Valve, of a guide secured to the end of the valve-axle,a thimble having loose connection with this guide, a segment having a slot therein and teeth thereon, and a lever pivoted to the segment and having a spring-latch adapted to engage the teeth, said lever having elongated slot adapted to receive and operate the thimble as the lever is swung, substantially as set forth.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

WILLIAM A. GRAHAM.

\Vitnesses:

O. S. DRURY, G. F. DOWNING. 

